Welding



April 22, 1941. c. A. CADWELL. 2,238,926

Y WELDING l Original Filed Oct. 22. 1936 4 vSheats-Sheetl INVENT OR.

April 22, 1941 c. A. cADwELL WELDING Original Filed Oct. 22, 1936 4Sheets-Sheet 2 R. n mw.. w m6 O MM 7 6 #M d 7 @oww April 22, 1941. .c A.CADWELL WELDING Original Filed Oct. 22, 1956 4 Sheets-Sheet 3 INVENTOR.

ATTORNEYS.

c. A. cADwELL 2,238,926

WELDING Original Filed 0G13. 22, 1936 4 Sheets-Sheet 4 INVENTOR.

ATTORNEYS.

Patented Apr. 22, 1941 WELDING Charles A. Cadwell, Cleveland Heights,Ohio, as-

signor to The Electric Railway Improvement Company, Cleveland, Ohio, acorporation of Ohio Application October 22, 1936, Serial No. 107,051Renewed April 19, 1939 2 Claims.

This invention relates as indicated to welding and more particularly tothat process oi welding wherein the weld metal is produced by means ofan exothermie reaction between a compounded metal and some strongreducing agent such as aluminum.

More specifically, this invention relates to a new and improved methodof and apparatus for securing rail bond conductors to rails utilizingthe above described form of welding operation to the production of animproved connection, both from a physical, as well as an electricalstandpoint between the rail bond and the rail. Certain aspects of thisinvention disclosed but not claimed herein are disclosed and claimed inmy co-pending applications Serial No. 243,351 iiled December 1, 1938,Serial No. 370,015 led December 13, 1940 and Serial No. 374,229 filedJanuary 13, 1941.

I am aware of the fact that workers in the prior art, as represented,for example, by the disclosure in U. S. Patent No. 1,007,005, haveattempted to utilize metal produced by means of an exothermic reactionfor attaching rail bond conductors to rails; however, such practice hasnot attained any commercial success due, it is believed, primarily tothe fact that such prior art practices have generally resulted in a bondstructure defective either from the standpoint of mechanical strength orelectrical conductivity, or both. The difficulty in providing a soundbond by the process under consideration is generally due to the factthat a stranded conductor body formed of copper is attempted to beattached to the solid body of the rail formed of steel. In other words,one of the elements is a more or less loose bundle of separate wires ofrelatively high thermal conductivity and the other member 1s a solidbody of considerably lower thermal conductivity. The fact that a properelectrical bond or connection should be established between each oi theindividual strands of the conductor body and the body of the rail properis perhaps as great a difliculty as any to be overcome in providing abond between the conductor body and the rail which has the requiredelectrical conductivity in addition to the necessary physical strength.

It is, therefore, a principal object of my invention to provide a methodof and apparatus for attaching rail bond conductors to rails, overcomingthe principal difficulties above enumerated and resulting in an entirelysatisfactory bond which may be produced economically and with suchfacility las to make the process usable commercially. Y

It is a further object of my invention to provide an apparatus for usein connection with the process comprising my invention, which apparatusis characterized by its relative simplicity and that it is readilyportable and thus capable ofv accordingly, its ease of manipulation andthe fact ready manualV manipulation in practice.

Other objects of my invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention,then consists of the means hereinafter fully described and particularlypointed out in the claims; the annexed drawings and the followingdescription setting forth in detail certain means and one modeillustrating, however, but one of the various ways in which theprinciple of the invention may be used.

In said annexed drawings:

Fig. 1 is a plan view of the preferred form of apparatus constructed inaccordance with the principles of my invention; Fig. 2 is a frontelevational view of such apparatus showing the same mounted impositionon a rail; Fig. 3 is a side elevational view showing the supportingrail' in section of the apparatus illustrated in Figs. 1 and 2; Fig. 4is a side elevational view of a modied form of apparatus constructed inaccordance with my invention; Fig. 5 is a side elevational view of theapparatus illustrated in Fig. 4; Fig. 6 is a broken, part sectional,part side elevational view of the apparatus illustrated in Figs. 4 and5; Fig. 7 is a transverse sectional View of the apparatus illustrated inFig. 6 taken on a plane substantially indicated by the line '1 -'1; Fig.8'is a transverse sectional view of the apparatus illustrated in Fig. 7taken on a plane substantially indicated by the line 8 8; Figs. 9 and 10are respectively plan and section views showing a form of crucible whichmay be employed in conjunction with the apparatus illustrated in theprevious figures; Fig. 11 is-a transverse sectional view of a packagecontaining a charge of exothermic powder usable in conjunction with themethod and apparatus of this invention; Fig. 12 is a fragmentary sideelevational view showing the type of connection between the rail bondand the rail resulting from the method and apparatus of my invention;Fig. 13 is an end elevation of yet another form of apparatus constructedin accordance with the principles of my invention; and Fig. 14 is a sideview of the apparatus shown in Fig. 13.

Broadly stated, this invention comprises the provision of a new methodof welding, as previously explained, characterized by the use of aparticular type of composition capable by means of an exothermicreaction to provide the` welding metal. This invention also comprises anovel method of introducing the weld metal to the rail and the bondconductor terminal desired to be attached thereto so that uponsolidication of the weld metal, a superior type of connection willresult. Further, as above indicated. this intrated in Fig. i to permitthe removal therefrom of the slag usually resulting from the exothermicreaction. 'I'he spring members 26 are mounted on each of the arms and 2land so arranged as to normally urge the sections B into engagement withthe sections A.

Carried by the fulcrum arms I2 is a U-shaped latch member generallyindicated at 29, the

erally indicated at I which consists of a main body 2 and an auxiliarygate member 3, the latter being resiliently secured to the former bymeans of springs such as 4 mounted on opposite sides thereof, attachedat its opposite ends to the members 2 and 3 respectively and enclosed ina suitable jacket such as 5 which precludes the spring from beingdamagedin the event molten metal should accidently come in contact therewith.

On the matrix face of the main mold body 2 there .is provided a cavity 6adapted to receive the terminal of the bond '|which is to be attached tothe rail 8. 'I'he exact form of such cavity may vary according to theparticular type of bond; however, a certain relationship between suchcavity-and the pouring sprue 9 should be maintained according to theparticulars hereinafter more fully explained. It will be noted that thepouring sprue 9 is formed as an open channel on the matrix face of themain mold section 2 and closed by the removable gate 3. The gate 3, i.e., one side of the pouring sprue 9, is made removable in order tofacilitate removal of the mold from the rail after the welding operationso that the metal remaining in the pouring sprue may be convenientlyremoved by chipping or the like from the main body ofthe bond terminala'fter the completion of the welding operation. f"

The mold I is secured by some suitable resilient means such as a springID'to the lower end of a fulcrum arm II. A second fulcrum arm, generallyindicated at l2, is, at its lower end, provided with a clamping foot I3adapted to engage the head and a face of the rail opposite to thatengaged by the mold I. A lateral extending arm I4 pivotally connects thefulcrum arms Il and I2 through the medium of the pivotal connection atI5. Extending between the upper ends of the fulcrum arms II and I2 is ascrew member IB having oppositely pitched threads on its opposite endswhich are respectively engaged in threaded blocks I1 and IB pivotallysupported on fulcrum arms II and I2. Intermediately of its ends thescrew member I6 is provided with a hand-wheel I9 whereby it may beconveniently rotated in veither direction to selectively move the upperends of the fulcrum arms towards and away from each other and tocorrespondingly unclamp and clamp the mold I against the face of therail.

Swingingly mounted on the fulcrum arm i2 are arms 20 and 2| respectivelyat their outer ends carrying crucibles 22 and 23. These crucibles arepreferably formed of some suitable refractory material such as graphiteand provided with a central recess such as 24 and an openingA lower ends3U and 3i of which are respectively adapted to be moved into and out ofthe path of movement-of the arms 20 and 2| to-retain the latter eitherin the open position as illustrated in full lines in Fig. 1 or in theclosed position as illustrated by the dotted lines in Fig. 1.

It will be noted that the form of apparatus ily lustrated in Figs. 1A to3 comprises two molds respectively supported on opposite vsides at thelower 4end of the fulcrum arm II and in such spaced relation that theopposite ends of the rail bond 'l may be simultaneously clamped andv thecrucibles move against the adjustable stop 32 as most clearlyillustrated in Fig. 3. 'I'he springs' 25 maintain vthe crucible sectionsB in engagement with the sections A` and when so positioned a metallicplug or gate 33 is placed over the outlet opening 25 in each crucible.'I'he foregoing sequence of events occurs, ofcourse, subsequent to aproper positioning of the apparatus on the rail and the placing of thesignal bond with its opposite ends in the spaced molds as illustrated inFigs. 1 and 2.

A charge of material preferably of the composition hereinafter morefully explained is then deposited in each of the crucibles and ignitedwhereupon the exothermic reaction thereof results in the formation of amass of very highly heated molten copper in the bottom of whichcrucible, the molten metal resulting from the exothermic reaction lneach crucible melts the plug or gate 33 in the bottom of each cruciblepermitting the molten metal to drop through the pouring sprue 9 into thecavity 6 in the manner hereinafter more particularly explained. thusfilling such cavity and upon subsequent cooling, provides a solidterminal bond 34, as most clearly illustrated ln Fig. 12 between thestranded body 'I and the rail 8. t

The apparatus illustrated in Figs. 4 to 8 is generally similar to thatillustrated in Figs. 1, 2 and 3 excepting that the crucibles withinwhich the exothermic reaction takes place are positioned at asubstantial elevation above the mold for the purpose hereinafter morefully explained.

Referring now more specifically to Figs. 4 to 8 inclusive the apparatusherein illustrated comprises paired molds generally indicated at 35which include a main mold body 36 provided on its matrix face with amold cavity 31 and a pouring sprue 38 leading upwardly therefrom. Thepouring sprue 38 is laterally closed by means of a removable gate 39.

The paired molds 35 are supported on the oppositely directed extensions40 on the lower end of the fulcrum arm 4I. The second v-fulcrum arm 42is provided at its lower end with a railengaging foot 43 and isintermediately of its ends pivotally connected as at M to the lateralextending arm 45 on the fulcrum arm- 4I. Be-

site directions at its opposite ends, the function and operation ofwhich is similar to the screw I6 previously described in connection withFigs.

As most clearly illustrated in Figs. 4 and 5, the fulcrum arm 4| isprovided with upwardly extending arms 41 which, at their upper ends,carry collars 48 within which are mounted vertically extending tubes 49.The tubes 49 are, at their lower ends, secured in collars 50 carried bythe upper portions of the molds 35.

Mounted on top of the tubes 49 are crucibles 5| within which arepositioned charges 52 which, upon completion of an exothermic reactionwill discharge quantities of very highly heated metal, such as copper,downwardly through the tubes 49, the pouring sprue 38 and into the moldcavity 31. The molds 35, similarly to the molds l of the apparatusillustrated in Fig. 1, are resiliently supported by means such assprings 40a on the lateral extensions 40 of the fulcrum arm 4|, suchsprings assisting in equalizing the pressure by means of which the twomolds are respectively clamped to the face of the rail. rI'he functionand operation of the apparatus illustrated in Figs. 4 to8 inclusive isgenerally similar to that of the apparatus illustrated in Figs. 1 to 3.The principal diiference being, as above indicated, that in theapparatus illustrated in Fig. 4, for example, the crucibles wherein theexothermic reaction takes place are at a considerably greater elevationabove the molds than in the apparatus illustrated, for example, inFig. 1. This elevation of the crucibles is desirable for certain typesof operation since the metal formed by the exothermic reaction indropping downwardly through the tubes 49 attains a suiicient velocity toimpinge with a considerably greater force against therail and the railbond terminal than in the apparatus illusangle against the face of therail to which the bond is .to be secured. Such impingement4 of themolten weld metal against the rail face, as well as the strandedconductor, as previously explained, improves .the atomic union betweenthe weld metal and the two elements which are sought to be joined.

Another form of apparatus constructed in accordance with the principlesof my invention and designed particularly for use in conjunction with acertain Vtype of conductor characterized by being generally larger thanthose with which the apparatus shown in Fig. 1, for example, isemployed, is shown in Figs. 13 and 14. The principal difference betweenthe construction illustrated in these last-named iigures and that shownlin Fig. 1

resides in the mold or molds generally indicated at 2a. The mold 2a isresiliently supported by means of the spring on a fulcrum arm insubstantially the same manner as in the apparatus shown in Fig. 1 sothat like reference characters will be employed to designate like parts.

The mold 2a formed of some suitable refractory material such as graphiteis divided into two sections 2b and 2c respectively, as most clearlyillustrated in Fig. 14. Sections 2b and 2c of the mold are provided withaxially aligned oppositetrated in Figs. 1 to 3. This acceleration of theweld metal prior to its introduction to the mold cavity may be foundadvantageous for certain types of bond and particularly where it isdesired to insure that'the weld metal will be forced into every 'recessnot only of the relatively narrow connes of the mold cavity but alsobetween the strands on the end of the bond.

The manner in which the mold cavities and the pouring sprues associatedtherewith are related, not only to each other, but also to the end ofthe bond being operated upon, is preferably the same in the variousforms of apparatus illustrated and is most-clearly shown in Fig. V6. Inythis last- ,named figure it will be noted that the pouring sprue entersthe mold cavity proper at such a position and in such a direction thatthe incoming highly heated weld metal resulting from the exothermicreaction flows in the mold cavity in a direction substantially axiallycounter to the end of the stranded conductor and also at an angle.

to the face of the rail to which the conductor is to be secured. It hasbeen found that thisA direction of flow of the weld metal in the mold isparticularly effective in insuring that the weld metal which forms thebond between the stranded conductor and the rail properly flows aroundand'- thus engages and makes electrical contact with each of the strandsof the conductor. In order to facilitate suchv action the end ofI thestranded conductor may be broomed out at least slightly, likewise asillustrated in Fig. 6.

It is desirable that the weld metal, as it ilows into the mold cavity,impinge at least at a slight ly threaded openings in which is positioneda screw 3b and by which the mold sections may be clamped together orseparated as desired.

'Ihe mold cavity generally indicated at 4b is different from the moldcavities of the previously described forms of construction in that thecavity in the apparatus illustrated in Figs. 13 and 14 is so formed thatwhen the mold sections 2b and 2c are brought together by the screw 3bthe end of the stranded conductor la extends towards the face of therail to which it is to be attached in a plane substantially normal tosuch face. With the mold cavity 4b formed in this manner, it is notlnecessary to provide a separate gate defining a pouring sprue, sincethe upper end of the mold cavity 4b is merely left open and serves asthe opening through which the highly heated metal is introduced into themold cavity and in a direction substantially axially opposed to the endof the conductor '|a.

The construction of the mold sections as shown in Figs. 13 and 14 is, aspreviously indicated, particularly desirable for,use in conjunction witha relatively large conductor, since when the conductor end is positionedin the manner illustrated in Fig. 13, the highly heated metal has abetter opportunity to flow around the end of the conductor and thusestablish the proper physical and electrical connection between theconductor and the rail.

The fact that the upper end of the mold cavity is open is alsoadvantageous in that any excess metal resulting from the exothermiccharge employed to generate the welding metal will flow laterally awayfrom the mold opening instead of building up as a column in a pouringsprue, thus reducing to a minimum the trimming necessary after thecasting operation has been completed.

In the light of the foregoing it will be noted that my inventioncontemplates the arrangement of the conductor end with respect to therail to which it is to be secured in a wide variety of ways, dependingupon the size and character of the conductor. All of these modificationsintroduced to the end of the conductor in a direction substantiallyaxially counter thereto.

In Fig. 1l, there is illustrated a cartridge 5I or package charge of thematerial used in accordance with my invention in providing the weldmetal. When such cartridge is employed, it will preferably be positionedin a crucible such as is generally illustrated in Figs. 9 and 10 andwhich has a conical inner surface. It has been observed in actual usethat a crucible having the type of inner surface illustrated in Figs. 9and 10, insures a better progression of the exothermic reaction than acrucible having straight sides.

The cartridge I illustrated in Fig. 11 cornprises side walls of somesuitable-material such as strawboard or the like with the top and bottomformed of a thinner material such as, .for example, Cellophane. Thecharge, generally indicated at 53, is preferably more firmly packedaround the outside of the container than in the center since it has beenfound that the igniting powder 54 shown positioned centrally of thecharge at the top of the container, when ignited, sets off the charge ina more efficient and more uniform manner than when the central portionof the charge is as tightly packed as the remainder.

As previously indicated, the top of the carton should preferably-be ofsome thin material so that it may be readily broken when it is desiredto ignite the ignitingpowder 54. The bottom 55 of the carton orcontainer for the charge is pref'- erably formed of some material whichwill either melt or decompose upon pyrolysis,. during or preferably uponthe completion of the exothermic reaction and without liberating anysubstantial amount of gas since it has been found that when.

the bottom of the carton-is made of some material such as strawboard,`the combustion of the same results in the generation of such volumes ofgas as to tend to blow the charge upwardly out of the crucible. 'I'hebottom 55 of the container, as above indicated, may be formed of somesuitable organic material such as Cellophane which has sufficientstrength but which.

will burn and permit the charge to drop out of the bottom of thecontainer without the generation of objectionable amounts of gas. It isto be noted that it is also within the contemplation of my invention toprovide the bottom 55 of the container with some suitable material as athin metallic sheet formed of either ferrous or nonferrous materialwhich will merely melt without th generation of any gas and permit theheated charge to drop downwardly therethrough.

I have also provided an improved mixture of components which, uponignition, will. proceed through an exothermic reaction to the productionof the desired quantity and qualityvof weld metal .for use in theprocess comprising my invention. A table giving the composition andproportion of such mixture is as follows:

Parts by weight Copper oxide (roasted copper mill scale) From about toabout 50 Copperaluminum alloy From about 14 to about 20 'Iin oxide Fromabout .75 to about 2 Y Zinc oxide From about .4 to about l Manganesedioxide-- Froml about .4 to about 1 As above indicated, the oxide ofcopper forming the principal constituent of the mixture and from whichthe principal volume of the resultant weld metal is derived ispreferably in the form aasaoae of roasted copper rolling mill scale.This metal scale is composed of fiat scales of various size and varyingdegrees of oxidation. The nner par ticles are black in color whichindicate a higher degree of oxidation than occurs in the larger scalesof red color. It is understood, of course, that while the metal scale isdesired and has been found highly satisfactory both from the standpointof its operation as well as its cost, pure C1120 may be employed.

The copper-aluminum alloy referred to in the foregoing table may containfrom about 50% to about '70% copper and from about 50% to about 30%aluminum, the preferred composition being about copper and about 35%aluminum. If the aluminum were present in granulated form, the rate ofreaction of the same with the copper oxide in the reduction of thelatter during the exothermic reaction would proceed at such a rapid ratethat the mixture during the course of the reaction would be blown out ofthe crucible. However, the use of this crushed or finely dividedcopper-aluminum alloy, instead of granulated aluminum as the reducingagent, reduces the violence of the reaction and adds volume to themiolten copper resulting from the exothermic reaction while permittingthe reaction to proceed at a sufficient rate to maintain the propertemperature necessary for the production of the molten welding metal.

In the foregoing table it should be noted that the tin oxide, the zincoxide and the manganese dioxide are all added `in accordance with theusual principles under which these elements are added to insure asoundness of the weld metal. Obviously, their proportional relationshipmay be changed if found necessary under particular conditions in orderto increase the soundness of the metal.

A specific example of a mixture yfound very satisfactoryfor use inaccordance with my invention is as follows The copper mill scale, aswell as thecopperaluminum alloy will preferably be in such finelydivided formas will pass through a 28 mesh screen and be retained on a100 mesh screen. The metallic manganese will be of such a iineness aswill pass through an 80 mesh screen.

The foregoing mixture does not ignite very readily, so that it isdesirable to employ in conjunction with each charge a small quantity ofan igniting powder wihch may be conveniently placed on top of the chargeignited with a match and which may, for example, contain the fol- Ilowing Parts by weight Copper oxide scale 20 Copper-aluminum alloy 5'Red phosphorus 5 Metallic aluminum powder '7.5 Black copper oxide 10weighed out and packaged, i. e.,provided in the form-illustrated in Fig.11 of the drawings, that not only will time be saved in the eld but ifthe charge is accurately weighed out and packaged, there will be greaterassurance that exactly the right amount of the charge will be employedas required to produce the amount of weld metal necessary to properlyfill the mold cavity.

While the above described invention has been explained by havingparticular reference tothe process of joining a .bond to a rail, it'willbe noted. however, that this invention is applicable to other uses thanthe one described such as, for example, in bonding the blades to thebase in an ordinary electric knife switch.

Instead of bonding the stranded conductor directly to the rail asexplained, my invention may, of course, be employed in bonding thestranded conductor to a steel plate or similar terminal member, whichterminal member is then secured by any suitalble means to the steelrail.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the means andthe steps herein disclosed, provided those stated by any of thefollowing claims or their equivalent be employed.

I, therefore, particularly point out and distinctly claim as myinvention:

1. The method of joining the conductor of a rail bond to a rail whichcomprises holding said conductor in place by means of a suitable moldclampedv against a surface of said rail and provided with an open cavityfacing the rail and in which the end of said conductor is positioned andthenI iillingV said cavity by means of a stream of heated metal, thedirection of flow of said stream of metal in said cavity being towardsthe said end of said conductor and in substantial alignment with theaxis thereof.

2. The method of joining the conductor of a rail bond to a rail whichcomprises holding said conductor in place by means of a suitable moldclamped against a surface of the rail and provided with an open cavityfacing the rail and in which the end of said terminal is positioned andthen by means of an exothermic reaction generating a charge of highlyheated metal and lling said cavity Aby means of said charge, the moltenmetal flowing in a stream into said cavity in a direction towards theend of said conductor and in substantial axial alignment therewith.

CHARLES A. CADWELL.

